{"title":"On the future of controllable fluid film bearings","authors":"I. Santos","doi":"10.1051/MECA/2011016","DOIUrl":"https://doi.org/10.1051/MECA/2011016","url":null,"abstract":"This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric actuators are used. The ideas of combining control techniques, informatics with hydrodynamic, thermo-hydrodynamic, elasto-hydrodynamic and thermo-elasto-hydrodynamic lubrication techniques are carefully explored in this paper, considering theoretical as well as experimental aspects. The main goal of using controllable fluid film bearings is to improve the overall machine performance by: controlling the lateral vibration of rigid and flexible rotating shafts; modifying bearing dynamic characteristics, such as stiffness and damping properties; increasing the rotational speed ranges by enhancing damping and eliminating instability problems, for example, by compensating cross-coupling destabilizing effects; reducing start-up torque and energy dissipation in bearings; compensating thermal effects. It is shown that such controllable fluid film bearings can act as “smart” machine components and be applied to rotating and reciprocating machines with the goal of avoiding unexpected stops of plants, performing rotor dynamic tests and identifying model parameters “on site”. Emphasis is given to the controllable lubrication (hybrid and active) applied to different types of oil film bearings under different lubrication regimes, i.e., as tilting-pad journal bearings, multi-recess journal bearings and plain journal bearings. After a comprehensive overview of the theoretical and experimental technological advancements achieved in university laboratories, the feasibility of industrial applications is highlighted, trying to foresee the future trends of such mechatronic devices.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"22 1","pages":"275-281"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81864820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Ghezal, Z. Ouchiha, B. Porterie, D. Veyret, J. Loraud
{"title":"Étude dynamique et thermique d’un écoulement pulsé en présence d’un solide chauffé en rotation","authors":"A. Ghezal, Z. Ouchiha, B. Porterie, D. Veyret, J. Loraud","doi":"10.1051/MECA/2011004","DOIUrl":"https://doi.org/10.1051/MECA/2011004","url":null,"abstract":"Ce travail s’interesse a un ecoulement autour d’un obstacle cylindro-conique chauffe, en rotation a l’interieur d’une cavite cylindrique. Il s’agit d’etudier l’influence d’une perturbation de type harmonique sur le comportement dynamique de l’ecoulement et sur le mecanisme de l’echange thermique avec l’obstacle. La frequence de reference de l’ecoulement periodique a ete determinee par l’analyse de l’evolution du regime vers son etat stationnaire. L’etude a ete menee pour des frequences variant de 1/3 de la frequence de reference a 10 fois cette derniere. La periodicite de l’ecoulement est assuree par la condition d’entree sur le debit suppose periodique. L’etude numerique a ete realisee pour des valeurs du nombre de Reynolds inferieur a 100 et pour des valeurs de nombre de Taylor inferieur a 500 afin d’eviter la presence des instabilites au sein de l’ecoulement. Deux methodes numeriques ont ete utilisees : une methode de differences-finies combinee avec un schema ADI et la methode des elements-finis. Le fluide considere est l’air avec des proprietes physiques constantes. Le couplage convection-conduction a ete considere dans une plage de variation du rapport K de la conductivite thermique du solide a celle du fluide de 10 -2 a 10 3 . Les resultats montrent que les composantes de la vitesse varient en phase avec le debit, alors que la pression et les differents parametres thermiques sont en dephasage avec la vitesse d’entree. On note aussi l’aspect periodique de tous les parametres dynamiques et thermiques de l’ecoulement pour les nombres de Reynolds utilises. L’influence de la frequence se manifeste davantage pour ses valeurs elevees. Le nombre de Nusselt est proportionnel a la frequence. Ces resultats sont en bon accord avec ceux donnees par d’autres etudes de reference.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"99 1","pages":"45-65"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89268433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comportement des matériaux cellulaires sous sollicitations dynamiques. Partie 2 : approche multi-échelles","authors":"Philippe Viot","doi":"10.1051/MECA/2011018","DOIUrl":"https://doi.org/10.1051/MECA/2011018","url":null,"abstract":"A multi scale methodology is proposed for the study of the cellular material behavior under dynamic loading. The behavior of polymeric foams studied depends on the constitutive material and the morphology of the porous structure. The cellular material of this study is constituted of millimetric porous beads, these beads are themselves constituted of microscopic closed cells. The methodology proposed to model the multi scale morphology of the structure (the scales of beads and cells) of the cellular material; it consists in implementing simple mechanical models at the different scales to reproduce the complex physical phenomenon observed and to model the macroscopic response of the foam. The observation and the analysis of physical phenomenon is the first step of the multi scale modeling. This paper describes the experimental and numerical methods used to observe and describe the structure of the cellular material, and quantify deformations and damages of these structures at the scales of beads and cells. Two ways of modeling were investigated: a finite-element model to represent the bead structure and another approach, more original, by the use of a modified discrete element model to model the microscopic structure of the cells.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"49 1","pages":"247-264"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81113523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tahar Rezoug, A. Benkhedda, M. Khodjet-kesba, E. Adda
{"title":"Analyse des plaques composites fissurées et vieillies en conditions hygrothermiques","authors":"Tahar Rezoug, A. Benkhedda, M. Khodjet-kesba, E. Adda","doi":"10.1051/MECA/2011134","DOIUrl":"https://doi.org/10.1051/MECA/2011134","url":null,"abstract":"Cet article concerne les composites stratifies croises constitues de plis unidirectionnels. Ces stratifies ont ete vieillis en conditions hygrothermiques par des conditions d’environnement variables. En effet les proprietes mecaniques des stratifies sont affectees par les variations de la temperature et de l’humidite. Lorsque des stratifies croises sont soumis a des sollicitations de traction quasi-statiques, le premier type d’endommagement qui apparait est la fissuration transversale des couches orientees a 90°. La presence de ce type de fissures entraine une diminution de la rigidite des stratifies. Dans cet article, un modele analytique fonde sur la diffusion du cisaillement a ete modifie pour evaluer la perte de rigidite des stratifies engendree par le vieillissement hygrothermique avec la variation transitoire de la concentration en fonction de la densite de fissures. Les resultats de cet article demontrent clairement la dependance de la degradation des proprietes elastiques en fonction de la densite de fissuration et des conditions environnementales.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"24 Sup9 1","pages":"395-398"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87767621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Avantages d’une configuration de machine à absorption opérant à trois niveaux de pression","authors":"N. Bouaziz, Ridha Ben Iffa, L. kairouani","doi":"10.1051/MECA/2011013","DOIUrl":"https://doi.org/10.1051/MECA/2011013","url":null,"abstract":"Cette etude presente une machine frigorifique fonctionnant suivant un cycle a compression-absorption. Le systeme propose utilise le couple ammoniac-eau comme fluide frigorigene et opere a trois niveaux de pression. L’absorbeur fonctionne a une pression intermediaire P int , prise entre la pression de l’evaporateur (PEV) et celle du condenseur (PCD). Les principaux elements du systeme propose sont modelises. Les resultats de la simulation numerique sont compares a ceux relatifs au systeme conventionnel. L’etude comparative met en evidence les avantages du systeme objet de cette etude. Elle prouve le double avantage de la pression intermediaire non seulement dans l’amelioration des performances de la machine a absorption mais aussi dans la reduction de la temperature du fonctionnement du generateur. Nous avons montre que pour des temperatures d’evaporation et de condensation prises respectivement a –10 °C et 40 °C, le cycle frigorifique fonctionne a une temperature du generateur TGE = 75 °C avec un COP de l’ordre de 0,56. La presente etude revele que pour les memes conditions de fonctionnement, la machine frigorifique simple etage, presente un COP qui ne depasse pas 0,51 avec une temperature du generateur de l’ordre de 135 °C. Le systeme hybride presente ainsi le privilege de fonctionner a basse temperature et de presenter des performances relativement ameliorees.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"84 1","pages":"103-107"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85563206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Experimental investigation on roundness error in friction drilling and mechanical properties of Al/SiCp-MMC composites","authors":"G. Somasundaram, S. Boopathy, K. Palanikumar","doi":"10.1051/MECA/2011141","DOIUrl":"https://doi.org/10.1051/MECA/2011141","url":null,"abstract":"Silicon carbide particulate reinforced aluminum (Al/SiCp) Metal Matrix Composites (MMC) is finding increased applications in Industries due to its unique advantages. Holes are to be drilled in many applications for joining and assembly purposes. Friction drilling is a newer non-traditional hole-making chip less process used to make holes in a single step. The manuscript first discusses the mechanical properties such as tensile strength and micro hardness of Al/SiCp-MMC composites, then it discusses the roundness (hole diameter accuracy) errors on dry friction drilled holes. The parameters considered for the experiments are: the composition of work piece, work piece thickness, spindle speed, and feed rate. The results indicated that the increase in the composition of wt% of SiCp particles increases the tensile strength, hardness. The drilling test results indicated that moderate wt% of SiCp gives better results. Higher spindle speeds and higher feed rates increase the roundness error. The highly influential parameter which affects the roundness error is feed rate. Increase in plate thickness also increases the roundness error in drilling of MMC composites.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"31 1","pages":"445-457"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87403896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"FSI methods for seismic analysis of sloshing tank problems (Corrigendum)","authors":"Z. Ozdemir, M. Souli, Y. Fahjan","doi":"10.1051/MECA/2011008","DOIUrl":"https://doi.org/10.1051/MECA/2011008","url":null,"abstract":"Acknowledgements. The authors would like to deeply thank Professor Sami A. Kilic and Bachelor of Science student Ceki Erginbas for the design of the experimental setup. The sloshing experiment was funded by Grant No. 07HT102 of the Bogazici University’s Research Fund (B.U. Arfon), for which Professor Kilic is the main investigator. The authors would like also to express their deepest gratitude to Professor Erdal Safak of Kandilli Observatory of Bogazici University for careful review of the manuscript and his valuable recommendations. This work is supported by the Scientific and Technological Research Council of Turkey (TUBITAK-MAG) through contract number 108M607 and by Research Fund of Gebze Institute of Technology under project number 2009-A-25. The first author is granted by Eiffel excellence scholarship of the French Ministry of Foreign and European Affairs.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"107 1","pages":"67-67"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80793490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optimisation de forme des structures hyperelastiques incompressibles et anisotropes","authors":"A. Jarraya, I. Kallel, F. Dammak","doi":"10.1051/MECA/2011127","DOIUrl":"https://doi.org/10.1051/MECA/2011127","url":null,"abstract":"Shape optimization of hyperelastic incompressible anisotropic structures. In this paper a shape optimization of hyperelastic incompressible anisotropic structures has been performed. The shape optimization program is implemented by a job control language and a reliable finite-element package program, the SQP (Sequential Quadratic Programming), is used for structural analysis. To achieve the shape optimization, different principles such as structural analysis, sensitivity analysis and mathematical programming are inter-related. The objective is to minimize the Von Mises criterium, with a constraint that the total material volume of the structure remains constant limit for each design variable. In this work, the sensitivity calculation is performed using two methods: numerically by an efficient finite difference scheme and by the exact Jacobian method. The feasibility of the proposed method is carried by a numerical example with anisotropic material.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"61 1","pages":"293-300"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81952156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Étude des performances de machines-outils 5 axes à structure parallèle et sérielle pour l’usinage d’une pièce aéronautique","authors":"Sylvain Pateloup, H. Chanal, Emmanuel Duc","doi":"10.1051/MECA/2011121","DOIUrl":"https://doi.org/10.1051/MECA/2011121","url":null,"abstract":"L’utilisation de machines-outils a structure parallele devrait permettre d’accroitre la productivite de l’usinage par rapport aux machines-outils a structure serielle pour des performances cinematiques des axes similaires. Ces machines-outils doivent cependant presenter une rigidite de leur structure, une precision de leur commande, et une accessibilite d’outil suffisantes pour l’usinage de pieces aeronautiques. Cet article propose alors de comparer les performances durant l’usinage d’une machine-outil 5 axes a structure parallele, la Tripteor X7 de PCI, et d’une machine-outil 5 axes a structure serielle, la KX15 de Huron. La comparaison est realisee a l’aide d’une piece test representative du secteur aeronautique. Les parametres evalues sont le temps d’usinage pour les differentes operations, la qualite dimensionnelle et geometrique de la piece realisee et l’etat de surface des surfaces obtenues. Ces essais illustrent le potentiel des machines-outils a structure parallele a usiner des pieces aeronautiques avec une qualite dimensionnelle et geometrique satisfaisante en augmentant la productivite. Cependant, la qualite d’etat de surface obtenue avec la machine-outil a structure parallele PCI Tripteor X7 n’est pas acceptable vis-a-vis des contraintes de qualite des pieces aeronautiques. Ainsi, plusieurs voies d’amelioration du processus d’usinage avec les machines-outils a structure parallele sont proposees afin de mieux maitriser la productivite et l’etat de surface obtenue durant l’usinage.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"41 1","pages":"479-486"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74818061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Étude du comportement mécanique d’un polyamide 66 chargé de fibres de verre courtes","authors":"Ghorbel Atidel, N. Saintier, A. Dhiab, F. Dammak","doi":"10.1051/MECA/2011104","DOIUrl":"https://doi.org/10.1051/MECA/2011104","url":null,"abstract":"Cette etude experimentale presente l’etude du comportement mecanique d’un polyamide 66 (PA66) renforce par des fibres de verre courtes frequemment utilisees dans l’industrie automobile. Afin d’etudier l’influence de la teneur en humidite, de la quantite de fibres de verre introduite dans la matrice et de la vitesse de deplacement, une serie d’essais de traction a ete realisee sur du polyamide renforce ou non avec des fibres de verre courtes a differents fractions volumiques : 10, 20 et 30 wt%. Les resultats montrent la dependance du materiau aux differents parametres cites precedemment. La technique de thermographie infrarouge (IR) a ete utilisee pour determiner l’evolution de la temperature a la surface des materiaux au cours des essais de traction. Un processus de localisation de la dissipation thermique a pu etre identifie a partir des images thermiques.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"25 1","pages":"333-342"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88454402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}